Polymer-based crosslinked networks with intrinsic self-repairing ability have emerged due to their built-in ability to repair physical damages. Here, novel dual sulfide-disulfide crosslinked networks (s-ssPxNs) are reported exhibiting rapid and room temperature self-healability within seconds to minutes, with no extra healing agents and no change under any environmental conditions. The method to synthesize these self-healable networks utilizes a combination of well-known crosslinking chemistry: photoinduced thiol-ene click-type radical addition, generating lightly sulfide-crosslinked polysulfide-based networks with excess thiols, and their oxidation, creating dynamic disulfide crosslinkages to yield the dual s-ssPxNs. The resulting s-ssPxN networks show rapid self-healing within 30 s to 30 min at room temperature, as well as self-healing elasticity with reversible viscoelastic properties. These results, combined with tunable self-healing kinetics, demonstrate the versatility of the method as a new means to synthesize smart multifunctional polymeric materials.

An extrinsic self-healing coating system containing tetraphenylethylene (TPE) in microcapsules was monitored by measuring aggregation-induced emission (AIE). The core healing agent comprised of methacryloxypropyl-terminated polydimethylsiloxane, styrene, benzoin isobutyl ether, and TPE was encapsulated in a urea-formaldehyde shell. The photoluminescence of the healing agent in the microcapsules was measured that the blue emission intensity dramatically increased and the storage modulus also increased up to 10 Pa after the photocuring. These results suggested that this formulation might be useful as a self-healing material and as an indicator of the self-healing process due to the dramatic change in fluorescence during photocuring. To examine the ability of the healing agent to repair damage to a coating, a self-healing coating containing embedded microcapsules was scribed with a razor. As the healing process proceeded, blue light fluorescence emission was observed at the scribed regions. This observation suggested that self-healing could be monitored using the AIE fluorescence.

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Back Cover: Dual sulfide–disulfide crosslinked s–ssPxN networks are synthesized by a combination of photo‐induced thiol‐ene radical addition and oxidation. These networks show rapid self‐healing at room temperature within 30 s to 30 min, with no need for extra heling agents. The self‐healable s‐ssPxN networks retain their integrity when damaged by external force and exhibit self‐healing elasticity with reversible viscoelastic properties. Further details can be found in the article by S. Y. An, S. M. Noh, J. H. Nam, J. K. Oh* on page 1255.